After guarding the abyss for a billion years, when he returned, his family became a criminal clan

My name is Meng Zhan. I traveled to a world with extremely high martial arts and became the eldest son of the Meng family of the Changsheng family. I have extraordinary talents, perfect birth, and super handsome person. I became the strongest son of God in the human race of the same generation. But when he reached adulthood, the system was activated and a mission was issued for him to go to the abyss and guard it for a billion years. As a genius of the human race, there is no turning back on this matter. So Meng Zhan joined the Demon Suppressing Army and stayed in Shenzhen...